One of the ancient methods of Iron Production in Japan is Tatara smelting process which used iron sands as raw mearial and charcoal as fuel. Recent archaeogical studies of iron production in Chugoku Mountains resulted in many important discoveries which fill the discontinuities in the history of Tatara iron smelting.Some of the most important discoveries are underground structure called Tokotsuri below the furnaces, sluicing method named Kanna-nagashi to separete iron sands from weathered granite, and charcoal production used iron smelting and iron refining.This research took up the kilns made charcoal for iron production. The charcoal used iron production are hard one called OHZUMI and soft one named KOZUMI.Ohzumi is used for iron smelting, Ozumi is for iron refining. We excavated some charcoal kilns for Ohzumi making in this year, Hiroshima prefecture.It is, however, yet unclear that when and where making charcoal as fuel used iron smelting, was originated in Japan. At present, we are sure that the charcoal making is dated back to Kofun period.